Implement indexOf and lastIndexOf using reference equality.

For observer lists, we do not care if two observers happen to
implement equals() such that they agree to be the same, we care 
only if they're the exact same observer.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1891 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/util/ObserverList.java

@@ -136,13 +136,13 @@ public class ObserverList<T> extends ArrayList<T>
         _allowDups = allowDups;
     }
 
-    // documentation inherited
+    @Override
     public void add (int index, T element)
     {
         throw new UnsupportedOperationException(UNSUPPORTED_ADD_MESSAGE);
     }
 
-    // documentation inherited
+    @Override
     public boolean add (T o)
     {
         // make sure we're not violating the list constraints
@@ -158,18 +158,44 @@ public class ObserverList<T> extends ArrayList<T>
         }
     }
 
-    // documentation inherited
+    @Override
     public boolean addAll (Collection<? extends T> c)
     {
         throw new UnsupportedOperationException(UNSUPPORTED_ADD_MESSAGE);
     }
 
-    // documentation inherited
+    @Override
     public boolean addAll (int index, Collection<? extends T> c)
     {
         throw new UnsupportedOperationException(UNSUPPORTED_ADD_MESSAGE);
     }
 
+    @Override
+    public int indexOf (Object element)
+    {
+        // indexOf and lastIndexOf are implemented using reference equality
+        // so that contains() also uses reference equality.
+        for (int ii = 0, nn = size(); ii < nn; ii++) {
+            if (element == get(ii)) {
+                return ii;
+            }
+        }
+        return -1;
+    }
+
+    @Override
+    public int lastIndexOf (Object element)
+    {
+        // indexOf and lastIndexOf are implemented using reference equality
+        // so that contains() also uses reference equality.
+        for (int ii = size() - 1; ii >= 0; ii--) {
+            if (element == get(ii)) {
+                return ii;
+            }
+        }
+        return -1;
+    }
+
     /**
      * Applies the supplied observer operation to all observers in the
      * list in a manner conforming to the notification ordering policy